weird, but my cel always been on for ,knock sensor,crank position sensor, and idle air control valve. well i filled up 93 octane chevron fuel and drove home removed my battery so i could start my mustang and when i put battery back in the check engine light never came back on. so i thought it would after 40 miles.


here i am 110 miles away and the CEL never came back on! why could that be? its not running better only better on gas its always ran perfectly smooth with the exception of the sometimes low or high idle in park.



its a 95 maxima automatic.

 

Your CEL will not come on for the knock sensor. Maybe bad gas was causing your problems. Those codes could still be there as ghost codes.

 

hmmm. thats weird lights been on the last 2 years that i've owned it. but i never thought about going to 93 octane until i read some old threads on here. seems to run the same but is better on gas.

 

It may not be gone for good. You probably just 'reset' the ecu by removing the battery. It will, in all likeliness, come back since you never actually fixed the problem.

 

Ive got a IACV and a set of CPS sensors for pretty cheap for ya PM me

 

I had the cel for the knock sensor and EGR solenoid valve since I bought the car and I replaced the EGR solenoid after reading some posts on here, the performance definitely improved with the change but the light stayed on.
After recently replacing my exhaust from the cat back, i started the car to take it down off of the ramps, the light did not come on and has been off since...go figure! I didn't unplug the battery or anything, so what the hell.

I'm glad it's at least gone, whatever the reason.

 

EGR can ghost a Knock Sensor.